This invention relates to hydraulic steering systems and, in particular, to multiple cylinder hydraulic steering systems typically used in marine craft such as boats with double or triple outboard engines or twin rudder inboard engines.
In a typical multiple cylinder hydraulic steering system, a second cylinder is piped in parallel with a first cylinder thereby increasing the cylinder volume supplied by the helm pump. This requires the use a helm pump that discharges a higher volume of hydraulic fluid per revolution, as compared to a helm pump used in a single cylinder hydraulic system, to keep the lock to lock turns within desired limits and generally equivalent to the number in a single cylinder system. As a result, an original equipment manufacture such as boat builder has to stock two or more types of helm pumps to deal with single cylinder systems and multiple cylinder systems.
There is therefore a need for multiple cylinder hydraulic steering system that may use the helm pump of a single cylinder hydraulic steering system.